Insights into lunar visibility, Islamic calendar precision, and the science of the crescent.
A complete guide to moon sighting: what it is, why it begins each Islamic month, the science of crescent visibility, why countries differ, and how to observe the hilal yourself.
The Moon sweeps from a high arc to a low one across the sky in just two weeks, while the Sun takes six months. Here is the astronomy behind the Moon's monthly arc cycle, and how to watch it in the Sky Dome.
Understand moon phases through phase angle, elongation, and illuminated fraction -- and how the geometry of each phase connects to crescent visibility, the Yallop q-value, and when the hilal appears.
A scientific deep dive into how Earth's atmosphere bends light near the horizon, how temperature and pressure alter the Moon's apparent position, and why refraction and extinction quietly reshape the numbers that feed crescent visibility models.
Can you see the crescent moon with the naked eye? Learn which Yallop zone needs which equipment, plus the best binoculars and telescopes for hilal hunting.
A scientific exploration of how observer elevation, horizon obstructions, and local topography dramatically affect crescent moon visibility, from horizon dip geometry to the physics of atmospheric extinction, and why hilltop observers consistently outperform those at sea level.
A scientific explanation of why the new crescent moon can be sighted in one country while remaining completely invisible in another, even on the same evening. Covers the role of longitude, latitude, the sunset sweep, moon age, and the geometry that creates global visibility zones.
When is Eid al-Fitr 2027 and Eid al-Adha 2027? Crescent forecasts, the likely dates, Arafah, and why your country may differ by a day.
Understanding the differences between Astronomical, Umm al-Qura, and Tabular calendar calculations, why they disagree, and how to read all three at once.
Everything you need to know to successfully observe the new crescent moon, from choosing the right location and timing your observation window, to scanning techniques used by expert hilāl hunters.
Master crescent observation and moon sighting scoring on moonsighting.live: Yallop zones, difficulty multipliers, worked examples. Build your log today.
A deep dive into the Danjon Limit, the hard physical boundary below which the crescent moon becomes invisible regardless of telescope power. Explore the lunar topography, optics, and modern CCD observations that define the absolute edge of crescent visibility.
How the Umm al-Qura calendar works, its exact astronomical rule since 1423 AH, why it does not guarantee crescent visibility, and the recurring Ramadan controversies.
Learn how to photograph the crescent moon with the right camera, lens and exposure settings, plus daytime infrared technique, stacking and safe Sun avoidance.
A comprehensive guide to the hilāl, the thin crescent moon that determines the start of every Islamic lunar month, from its Quranic origins to the modern astronomy behind predicting its visibility.
A journey through 4,000 years of crescent moon observation, from ancient Mesopotamian astronomers who recorded lunar data on clay tablets, through medieval Islamic scholars who built the first visibility theories, to modern CCD cameras and crowdsourced global networks.
Watch global moon sighting reports roll in live on the 29th night. Discover how sunset sweeps east to west, giving western observers extra elongation and turning a local act into a planet-wide wave.
Who saw the youngest crescent moon ever? Verified naked-eye, optical-aid and photographic records, from O'Meara to Legault, with the science of how thin a hilal can be.
A deep dive into how Hilal Vision predicts the visibility of the new crescent moon using the Yallop q-value and Odeh V-value criteria, ARCL, crescent width, and the Danjon limit.
How the Islamic Crescents' Observation Project collects, cross-checks, and publishes crescent sighting data across 1418 to 1447 AH, and what the archive reveals about the Yallop and Odeh models.
Ramadan 2027 (1448 AH) is expected to begin on Monday 8 February 2027. Here is the verified moon-sighting geometry, why the date is a forecast and how to track it live.
Why do Muslims start Ramadan on different days? A clear, sourced guide to global vs local moon sighting, calculation, the Saudi declaration and the science of disputes.
An objective, scientifically grounded analysis of the longstanding debate between physical moon sighting and astronomical calculation for determining Islamic months, examining the evidence, accuracy, and limitations on each side.
A researcher-grade guide to global versus local moon sighting (matla): the fiqh of ittihad and ikhtilaf al-matali, Wujud al-Hilal vs Imkan al-Rukya, and unified calendar proposals.
An in-depth exploration of the Islamic Hijri calendar, how lunar months are determined, why there are multiple systems, and the science behind the ongoing debate between astronomical calculation and physical sighting.